Conventionally, for example, as described in Japanese Patent Application Publication No. 2003-81461, as a sheet take-out apparatus, an apparatus including a feed-out roller rotating in contact with a sheet at one end in the stacking direction, thereby feeding out the concerned sheet, a take-out roller for rotating in contact with the fed-out sheet, thereby taking out the concerned sheet on a conveying route, a separation roller for separating sheets pressed to the take-out roller via the conveying route and given separation force in the reverse direction, thereby overlapped, and a conveying roller for conveying sheets passing a nip between the take-out roller and the separation roller is known.
In this apparatus, when a sheet conveyed by the conveying roller is detected, the take-out roller is rotated reversely, thus overlapping sheets can be easily separated by the separation roller.
However, in this apparatus, overlapping sheets which cannot be separated by the separation roller are conveyed straight to the later stage of processor via the conveying roller. The sheets conveyed in the overlapping state cause jamming in conveyance.
Therefore, it may be considered to add a re-separation unit for re-separating overlapping sheets passing through the separation roller. However the apparatus constitution is complicated and a new problem arises that the cost of apparatus is increased.
Further, overlapping sheets are generally rejected during conveyance and are removed from processing objects, so that when overlapping of sheets occurs, the rejected sheets must be re-supplied and processed. Thus a problem arises that the processing capacity of the apparatus is reduced.